It was one of "48 Hours"' most astonishing interviews: beautiful, young Jodi Arias describing how her ex-boyfriend, Travis Alexander, was murdered in cold blood during a home invasion and how she managed to barely escape with her life.

Now, four years later, it's Arias who's on trial for that very same murder -- fighting for her life in a Phoenix, Ariz., courtroom.

"48 Hours" takes you inside the trial that has captured national attention and inside the mind of an accused murderer with Arias' first interview, done with "48 Hours" shortly after her arrest in 2008 -- an interview so important that it has been obtained as evidence by both the prosecution and the defense.

For the last two-and-a-half weeks, Jodi Arias has been sitting quietly in a courtroom, patiently listening to the evidence against her.

But Arias is no stranger to patience. She has spent the last four years in jail, waiting for her trial to start and wondering just how she ended up here in the first place.

"I've been sitting a lot in my cell ... thinking what a waste," she told correspondent Maureen Maher. "You know, I did have my whole future ahead of me ...I had everything to lose and nothing to gain if I killed Travis. I loved him and I still love him".

Travis Alexander and Jodi Arias seemed, by all appearances, to be a perfect match.

Hughes added Travis to his sales team at Pre-Paid Legal Services Inc., a company that sells legal services insurance to people who can't afford lawyers.

"He was such a powerful motivational speaker that, you know, he could move us to tears," said Arias.

On the surface, it seemed they had little in common. Arias was raised in the quiet community of Yreka in Northern California, describing her childhood as "almost ideal. I have a big family. We're all very close."

But they found a strong connection in their drive to succeed.

"We both had a desire to - to -- really do amazing things in our lives," she explained.

In no time, Arias began to make his world her own.

"He gave me a copy of the "Book of Mormon" ...and challenged me to read it," she said.

Following Travis' lead, Arias converted to the Mormon faith.

"You know we grew closer and closer and it was a natural progression," she said. "It was a serious relationship."

But this couple had a big obstacle to overcome -- 400 miles of open road. Travis lived in Mesa, Ariz., while Arias was a five-hour drive away in Palm Desert, Calif.

But Travis overcame that obstacle as well; he took his relationship with Arias on the road.

"He called me up one day. He said, 'There's this great book that I found, and it's "1,000 Places To See Before You Die,"' Arias said. "And so we began to check those places off the list one by one."

But it turns out that Travis and Jodi were doing a lot more than just sightseeing.

"There was an attraction. And, you know, it -- it found an outlet on occasion," Arias said with a laugh.

"That's a very creative way of saying it," Maher laughed. "It found an outlet."

Most young couples would call that "outlet" sex, but for Travis and Jodi, as devout Mormons, sex outside of marriage was taboo.

Celibacy is one of the basic tenets of the Mormon faith -- one that, as far as his friends and family knew, Travis took very seriously.

"It was a core piece of Travis' belief to not have any kind of sexual relations with anyone that you're not married to," said Taylor Searle.

Searle, Brint Hiatt and Aaron Mortenson knew and respected Travis as a close friend and fellow Mormon.

"We all looked out for Travis. You know, we wanted him to find ...and settle down with a great girl," said Hiatt.

"It was important for him to be married to a Mormon, and to have children, and remain in the church?" Maher asked.

"That was always a goal of his - absolutely," Mortenson replied. "...to find a girl that was gonna be a good match for him and -- marry her."

"When I met Jodi," Searle said, "she kind of announced herself as his girlfriend. And -- that was a surprise to me at the time 'cause I thought he, you know, had interest in some other girls."

"He definitely played the field," added Hiatt.

Jodi Arias was beginning to realize that as well. "There's sort of a distinctive feeling that comes when you're in a relationship and you have that sneaky suspicion that somebody might be not so -- monogamous. And so --"

Arias suspected Travis was cheating on her.

"I grabbed his phone while he was taking a nap, and I just started reading his text messages. And I was really shocked with what I found," she told Maher.

"That's what basically ended his relationship, whatever it was ... with Jodi," said Searle.

Well, not exactly. Shortly after their breakup, Jodi made a surprising decision. She packed up her belongings and moved right under Travis' nose, to Mesa, Arizona -- a move, she says, Travis strongly encouraged.

"There were also some innuendos, I think, as far as we could still hang out," said Arias.

Arias says that she was becoming increasingly uncomfortable with a sexual relationship that seemed to be going nowhere.

"You know you love someone and - you -- it makes -- you know, it's hard to think. And I really love this person, but I know I'm never gonna be with him. And I know I'm not gonna marry him," Arias said. "I knew that I needed to make some changes."

Early in 2008, Jodi did just that. Doing them both a favor, she moved back home to Yreka, leaving Mesa and Travis Alexander behind.

"When she moved back to California, that's when it really seemed to him to be a closing point. Where, 'OK, finally that chapter of my life is over,'" according to Searle.

But as it would turn out, the story of Travis and Jodi was far from over.